Effect of observed individual data of performance and excretion on life cycle assessment of piglets

Abstract

The objective was to evaluate the impact of producing piglets fed diets with different crude protein (CP) levels through life cycle assessment and experimental data. In Trial I (performance), 28 crossbred barrow piglets, with an initial average weight of 15.3 ± 1.15 kg were divided into a randomized block design with four treatments, seven replications and one animal per experimental unit. In Trial II (nitrogen and phosphorus balance), 20 crossbred barrow piglets with an average weight of 21.4 ± 1.62 kg were divided in a randomized block design with four treatments, five replications and one animal per experimental unit. Four experimental feeds were evaluated: HighCP, CP18, CP17 and LowCP, with 19, 18, 17 and 16 % of CP, meeting the requirements of digestible amino acids through industrial amino acid (IAA) addition. From Trial I and II data, the environmental impact was calculated for global warming potential, acidification potential, eutrophication potential, cumulative energy demand, terrestrial ecotoxicity and land occupation (LO). Total nitrogen excretion decreased by 0.226 g d -1 for each 1 g of reduction on daily nitrogen intake. However, there was no statistical difference (p > 0.05) among experimental treatments for all impact categories. For LO, there was a reduction (p = 0.078) of impact with CP reduction, which was 8 % lower with the LowCP diet, in comparison with HighCP. Dietary CP reduction for piglets from 15 to 30 kg, through IAA supplementation, reduced the environmental impact under LO, considering soybean meal from southern Brazil and observed individual data of performance and excretion.

The Reduction of Crude Protein with the Supplementation of Amino Acids in the Diet Reduces the Environmental Impact of Growing Pigs Production Evaluated through Life Cycle Assessment

“…For the GWP category, the results varied between 2.95 and 2.80 kg CO 2 -eq. of LWG, higher than those reported by Monteiro et al [7], which can be related to the worsening in feed conversion and the higher excretion of N in the current study. Higher results for this category were obtained by Bandekar et al [36]; however, besides using dried distiller grains with solubles as the main protein source in the diets, the authors showed results for the LCA in different stages of creation (gestation, lactation, growing and finishing), in addition to different managements performed in each phase, such as comparison between sows managed in cages or in groups, diets without the use of growth promoters, immunocastrated or surgically castrated animals and evaluation of the use of ractopamine.…”

“…The higher excretion of N for animals fed the high levels of CP diets was also observed by Monteiro et al [7], who found total excretion of N varying from 8.22 to 5.84 g/d in diets with 19 and 16% CP, respectively. However, these authors evaluated the protein reduction for lighter pigs (15 to 30 kg).…”

“…To obtain the data for this study, a metabolism experiment was carried out to evaluate the digestibility of nutrients present in the diets, and a second experiment to evaluate the animal performance. Experiments with similar objectives to those proposed in the present study have already been carried out by Reckmann et al [9] and Monteiro et al [7]. In the first study, the authors assumed that protein reduction does not influence the performance of animals, since nutritional requirements were met in all diets.…”

“…Much of the environmental impact caused by pig production occurs during the cultivation period of the ingredients used in the pigs' feed [2,7]. However, due to the large amount of manure generated in the animal production stage and the potential impact on air, water and soil, this stage has been the focus of public discussions.…”

“…The problem is that manure generated in the production stage, such as nitrogen (N), phosphorus (P) and zinc, can cause acidification, eutrophication and ecotoxicity of the environment. Thus, changes in the nutritional composition of the feed can lead to significant differences in the environmental impact caused by the production of pigs, since they will affect the inclusion of ingredients and, consequently, the demand for their production, as well as the digestibility of nutrients such as N and P [7,8].…”